There are a multiplicity of microorganisms which colonize on surfaces and propagate to form biofilms. Such colonization may be unwanted for a large number of reasons, such as, for example, hygiene concerns in the case of medical articles or transport materials and packaging materials for foodstuffs and comestibles, or economic considerations in the case of boat hulls.
One way of avoiding colonization by microorganisms is the regular treatment of at-risk surfaces with disinfectants for external application. Disadvantages of a procedure of this kind include the need for frequent repetition of the treatment, the difficulty of estimating the amounts required, and the often unhealthy qualities of the disinfectants.
Another way of avoiding colonization by microorganisms is to use materials whose surfaces are biocidally active. Such materials can be produced, for instance, by incorporating biocidally active substances into a base material. Organometallic compounds, metal salts of tin, silver or copper, for example, or specific organic compounds are known to act as biocides. When such compounds are admixed to a plastic or to a surface coating, a decay-inhibiting or biocidal activity is obtained. According to U.S. Pat. No. 4,532,269, for example, a terpolymer of butyl methacrylate, tributyltin methacrylate, and tert-butylaminoethyl methacrylate can be used as an antimicrobial marine coating. Disadvantages of such materials reside in the decrease in their biocidal activity over time, since the concentration of the biocidal substances in the base material diseappears continuously through diffusion and leaching, and in the environmental pollution associated with this release of the biocidal substances.
Moreover, polymer materials having biocidal properties can be obtained by using monomers substituted with biocidally active groups to produce said materials. In this case the biocidal activity is long-lasting and is not reduced by gradual leaching and diffusion.
Accordingly, EP0862858 describes a copolymer of tert-butylaminoethyl methacrylate and aliphatically unsaturated monomers. WO0118077 discloses a homopolymer of acryloyloxy-alkylamines or methacryloyloxyalkylamines.
Ilker et al., Macromolecules 2004, 37, 694-700, disclose antibacterial polymers of cyclic anhydrides or imides based on norbornene.